Propulsion units, such as ducted fans and jet engines, typically include a nozzle on the exhaust end thereof that receives a flow of fluid (e.g., air and/or exhaust gases). Such nozzles enhance propulsion by constricting or diffusing fluid flow. The characteristics of the resulting fluid jet, such as pressure, velocity and direction, may be a function of the overall shape of the nozzle, as well as the cross-sectional area of the throat of the nozzle.
In a variable area nozzle, the cross-sectional area of the throat of the nozzle may be varied in real time. For example, depending on operating conditions at a given time, the cross-sectional area of the throat may be increased (diverged) or decreased (converged). Such real-time control of the nozzle may enhance propulsion performance and overall operating efficiency.
A typical variable area fan nozzle is constructed from a series of overlapping pedals that may reduce the cross-sectional area of the throat of the nozzle. A series of actuators is required to manipulate the pedals as desired. The actuators and associated hardware used to couple the actuators to the pedals add complexity and significantly increase the overall weight of the nozzle.
Accordingly, those skilled in the art continue with research and development efforts in the field of nozzles.